Stellavox SU-8

The Stellavox was the only true alternative to the Nagra portable audio recorder.

Also made in Switzerland and reputedly by some ex-Nagra employees, these machines were more compact, rather better finished and felt perhaps more developed than the Nagra. It was as if Nagra had left their own masterpiece slightly unfinished and that the Stellavox was something of an

advanced refinement. But things are never that simple and in addition to the interesting relationship that existed between these two companies, their products also show quite strongly

differing personalities. As an amateur enthusiast I was inclined to think that the Stellavox was the best portable reel-to-reel recorder ever made. It certainly was a very expensive and rare beast, and when I had the opportunity to acquire one of these Swiss portable recorders, it was a Stellavox that I went for. However, I was not going to earn my living with it or try and build a reputation with one. But I imagine that many professionals did, and having had the chance recently to re-acquaint myself with some Nagra machines, I concluded that they were just differing 'solutions' to a similar set of problems. Unfortunately I did not have the opportunity to compare their audio quality, but have included their specifications on the site.

An impression might be formed that the smaller and more compact Stellavox recorder seems to contain rather more contradictions in it's make up. I believe that it was not as well accepted in the film industry or as widely known generally (though this could be down to discontinuities of representation, at least in the UK). but they were used when a highly portable, non sync but high performance audio recorder was needed. Like the Nagra, variations of the Stellavox were made for multi-channel instrumentation recording, and there were versions for 4 track 'Quadraphonic' as well as highest quality stereo mastering (this version was known as the 'Stellamaster'). Subject to encouraging though mixed reviews by Hugh Ford in Studio Sound in the early 1970's, to use a Stellavox was to be rather 'different', which perhaps was also part of their attraction. However on these pages are examples of both the Nagra and the Stellavox, so perhaps some own conclusions may be drawn.

The father of the Stellavox, Mr Georges Quellet himself was kind enough to send me this image of his earlier SM5 recorder*.

It would seem that in 1950's in addition to those in America and Britain, a number of people in Switzerland were also developing high quality reel-to-reel magnetic tape recorders. Whereas Mr Studer would go on to produce his superb professional full size machines, Stephan Kudelski and

Georges Quellet made far more 'pocketable' tape recorders. As a school boy I can also just remember the British Fi-cord brand of miniature audio recorders, though 30 years later I found out that these tiny exotic machines were also made in Switzerland (by Georges Quillet it would appear). It was though perhaps obvious that the combination of miniature electronics and precision mechanics needed to make a high quality tape recorder would suit a country also known for watchmaking, and one could argue that the end results would be some of the finest examples of 20th Century electro-mechanical engineering.

* It is possible that he will collaborate in a book about hs machines, do please let me know if you think this a worthwhile project and I can advise the author.

But the machine is very compact, and does have a fairly significant amount of conventional wiring inside. I once used to wire medical electronics for a living, and can only look at the Stellavox's internal 'spaghetti with some respect for those who knitted it all together (much better done though than the rat's nest to be found in much domestic electronics). And admittedly also with some concern if ever I had to do some serious fault finding in there... Yes the electronics is mostly modular plug in units, but what about the rest of it? Mind you the Nagra is also looks quite involved as well...

The above picture is my own Stellavox SU8, and this was one of the last models from the original Stellavox company, this particular example dates from the mid 1980's. The 'U' stands

for universal, because this version of the recorder came 'loaded' with a full range of modules and options as follows:

MSP module - switchable mono, stereo, 'snchrotone' and 'neopilot' head assembly

SXQ module - crystal pilot tone generator

SQS module - in-built synchronizer module and associated front panel controls

SOT option - balanced 600 Ohm input/output transformers and seperate connections.

AMC tape counter unit

The recorder also has switchable 48V phantom or 'T' microphone powering together with a two position low frequency microphone filter, peak limiters and three position gain attenuators (these were fairly standard options I believe). The microphone gain controls have the optional 'ganged' gearing arrangement, and can be mixed with adjustable line inputs. Stellavox also made a recorder powered external microphone pre-amplifier (and various other external modules), so that one could have a fairly self-contained set of 4 microphone inputs if required. Oh, and the moulded plastic reel cover had the machined-satin-chromed 'thingy' fitted, for actuating the slate toggle while the machine is sitting in its leather case.

The recorder's specifications may be found here.

Portable Reel-To-Reel Audio Tape Recorder

The above picture is my own Stellavox SU8, and this was one of the last models from the original Stellavox company, this particular example dates from the mid 1980's. The 'U' stands

for universal, because this version of the recorder came 'loaded' with a full range of modules and options as follows:

MSP module - switchable mono, stereo, 'snchrotone' and 'neopilot' head assembly

SXQ module - crystal pilot tone generator

SQS module - in-built synchronizer module and associated front panel controls

SOT option - balanced 600 Ohm input/output transformers and seperate connections.

AMC tape counter unit

The recorder also has switchable 48V phantom or 'T' microphone powering together with a two position low frequency microphone filter, peak limiters and three position gain attenuators (these were fairly standard options I beleive). The microphone gain controls have the optional 'ganged' gearing arrangement, and can be mixed with adjustable line inputs. Stellavox also made a recorder powered external microphone pre-amplifier (and various other external modules), so that one could have a fairly self-contained set of 4 microphone inputs if required. Oh, and the

moulded plastic reel cover had the machined-satin-chromed 'thingy' fitted, for actuating the slate toggle while the machine is sitting in its leather case.

It would seem that in 1950's in addition to those in America and Britain a number of people in Switzerland were also developing high quality reel-to-reel magnetic tape recorders. Whereas Mr

Studer would go on to produce his superb professional full size machines, Stephan Kudelski and Georges Quellet made far more 'pocketable' tape recorders. As a school boy I can also just

remember the British Fi-cord brand of miniature audio recorders, though 30 years later I found out that these tiny exotic machines were also made in Switzerland (by Georges Quillet it would

appear). It was though perhaps obvious that the combination of minature electronics and precision mechanics needed to make a high quality tape recorder would suit a country also known for

watchmaking, and one could argue that the end results would be some of the finest examples of 20th Century electro-mechanical engineering.

* It is possible that he will collaborate in a book about his machines, do please let me know if you think this a worthwhile project and I can advise the author.

I am told that Mr Quellet was proud of the robust, compact and recessed control panel of his recorder. In contrast to the unique coaxial peak metering of the Nagra, Stellavox used an opposing pair of conventional VU meters. Though in this model there are also a couple of peak indicating LEDs. These actually show the limiters in action if that mode is selected. This machine also has the extra LED and meter rotary switch for the in-built pilot tone resolver. The circular disk between the microphone gain controls is actually a gear wheel that can be pushed inwards to engage with the transparent 'gears' surrounding these controls to 'gang' them together.

Here is a view of the right side of the machine, with (left to right) speed change switch, balanced 600 Ohm input and output 4mm sockets and headphone socket with volume + mode controls (left only, right only, stereo).

Left side of the machine containing input and outputs: power, sync heads, line outs/external noise reduction loops, and microphone inputs. There is also a mono/stereo switch and a 2

position bass cut switch. The vertical pin on the extreme right is one of the carrying strap attachment points.

A view of the underside of the Stellavox SU8 with the bottom plate removed.

Like the equivalent Nagra, the Stellavox had a single servo motor with an optical tachometer. Tape transport was by a single capstan and belt driven reel hubs. In fact a single duplicated drive belt was used, presumably to allow for breakages. Tape tensions were controlled by mechanical idle-roller governed slipping clutches. The electrially switched rewind was quite rapid and the tape was removed from the audio heads, but fast forward was just done by putting the motor into a high forward speed (at slightly over 30 I.P.S.), though this was similar to the way Nagra did things. A feature of the Stellavox was the way that it smoothly moved the pinch and flutter rollers into and away from the run position. This was done by a beautifully engineered sectored gear mechanism driven from the capstan shaft. Of course no pressure pads were used.

Rather more modular internally in comparison to the Nagra, most of the electronics are built inside a number of plug-in screened metal cans. There is a large and complex mother board fixed

directly under the deck plate, and these various screened modules plug into best quality gold-plated edge connectors. The modules are securely held in place by the foam lined bottom cover. The Stellavox was appreciably smaller and more compact than the equivalent Nagra portable, and therefore was rather more 'busy' inside, and probably something of a challenge to fault find

and repair. The early electronic modules were encapsulated in resin and had to be returned to the factory for replacement, but the resin was left out of the later machines. Apart from the

theoretically increased reliability of encapsulation, it was reputed that Mr Quellet was very proud of his circuitry and understandably did not wish his good work to be easily acquired by competitors. And I imagine that that is the reason that most electronics are covered with resin...

My own general impression is that the Stellavox seems rather stronger and more 'developed' than the Nagra, and is in some ways rather nicer and more 'finished'. It certianly looks much less of a 'Meccano set'. But as these machines were very serious work tools and not jewelry, it could be argued that function, reliability and ease of servicing were far more important than look.

This is the underside of the supply reel hub area, with pivoting brake lever and rather fine red felt brake 'shoe'. Hold-back tension is controlled by the pivoting arm of the supply tension roller above the deck plate (out of shot at the left of the picture) 'pulling' on one end of the brake lever via the red sleeved wire and pulley (bottom centre). This varies the amount of breaking force

applied to the shoe by a helical tension spring. The engineering aspects of this machine are simple and nicely done. For example see also the underside of the tape counter below:

But the machine is very compact, and does have a fairly significant amount of conventional wiring inside. I once used to wire medical electronics for a living, and can only look at the

Stellavox's internal 'spaghetti with some respect for those who knitted it all together (much better done though than the rat's nest to be found in much domestic electronics). And admittedly

also with some concern if ever I had to do some serious fault finding in there... Yes the electronics is mostly modular plug in units, but what about the rest of it? Mind you the Nagra is

also looks quite involved as well...

Above is the drive/capstan motor looking towards the main function control switch. The quality of components is every bit as good as those used in the Nagra, perhaps better in some places. I like that spiral earth wire onto the motor casing.

Below is the underside of the rather nice cast plug-in head block 'module'.

These easily changed though expensive, these self-contained units came in a number of favours depending on the format the machine would be working with (mono, stereo, half or full track,

music mastering, film recording etc), tape speed (and thus equalization) and tape type (bias level). The idea was that while the machine's 'mainframe' had indeed 4 switched motor speeds, you actually changed the head blocks to change tape speed or tape type.

This was very simple and elegant and it avoided what might prove to be expensive and

embarrassing mix ups (the BBC completely removed the speed change system on their Uhers for the same reasons), but only if you had the cash to afford the additional head blocks at around £600 a time. Though the professional user would perhaps need only one or two modules; film sound recording was standardized at 7.5 inches per second, and music recording 15. Tape was usually standardized on one specific type and obtained in bulk, so there was no need to be able to change bias easily. And of course many an untrained 'twiddler' has mucked up bias and equalization settings on otherwise perfectly good machines - I should know!

With a power supply the Stellavox could even work at 30 I.P.S., and there was a 10 Inch reel adapter to take advantage of the higher speeds, you would of course need the correct head block.

Sadly though Stellavox never did sort out their large reel adapter which was in in comparison to the superb Nagra version, was rather a joke.

This is an inverted view of the MSP head block, which was fitted to the Stellavox SU8 and SP8 TC. It is switchable to work with mono 'Neopilot', stereo 'Synchrotone' and mono 'Synchrotone'.

The Neopilot/Synchrotone heads (brass coloured ones in the picture) can also be used to record/replay time code. Without the exotic Ruby tape guides of the Nagra, the three stainless

steel versions used in the Sellavox also seem fairly adiquate, perhaps one might like to compare this head assembly with the Nagra T-Audio head block. Below is a view of the Stellavox head

block with the top cover removed. The presets are for equlization and record level adjustment.